Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
Processing...

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:\n" + " <\\?php\n" + " (?:\n" + " [^\"'\\/<\\?]+\n" + " |\n" + " (?:\n" + " \"(?:[^\\\\\"]|\\\\[\\s\\S])*\"\n" + " |\n" + " # '(?:[^\\\\']|\\\\[\\s\\S])*'\n" + " #|\n" + " \\/\\*(?:[^\\*]|\\*[^\\/])*\\*\\/ \n" + " |\n" + " (?:\\#|\\/\\/).+(?:\\n|$)\n" + " |\n" + " (?:\n" + " <<<\\s*\n" + " (?:\n" + " (?:'([a-zA-Z0-9_]+)'\\s*?\\n)(?:[^\\n]*\\n)*?\\s*\\1\\s*?;?\\s*?(?:\\n|$)\n" + " |\n" + " (?:([a-zA-Z0-9_]+)\\s*?\\n)(?:[^\\n]*\\n)*?\\s*\\2\\s*?;?\\s*?(?:\\n|$)\n" + " )\n" + " )\n" + " )\n" + " |\n" + " (?:[^?]|\\?[^>])\n" + " )*\n" + " (?:\\?>|$)\n" + ")"; final String string = "<!--\n" + " The PHP masterpage\n" + "-->\n" + "<?php\n" + "$matches = array();\n" + "// separates \n" + "$re = <<<PREG\n" + " /^\n" + " \n" + " (?:\\\\s*(?:<!--.*?-->))*\n" + " <\\\\?php\\\\s*include\\\\s*(\\\\()?\\\\s*([\\\\'\\\\\"])(?:(?!\\\\2).)*(?-i)Master\\\\.php(?i)\\\\2(?(-2)\\\\))\\\\s*;\\\\s*\\\\?>\\\\s*\n" + " (?:\\\\s*(?:<!--.*?-->))*\n" + " <master\\\\s*src=([\\\\'\\\\\\\"])(?<master_url>.+?)\\\\3\\\\/>(?<content>[\\s\\S]*)\n" + " $\n" + " /ix\n" + "PREG;\n\n\n" + "$re = <<<PREG2\n" + " /^\n" + " \n" + " (?:\\\\s*(?:<!--.*?-->))*\n" + " <\\\\?php\\\\s*include\\\\s*(\\\\()?\\\\s*([\\\\'\\\\\"])(?:(?!\\\\2).)*(?-i)Master\\\\.php(?i)\\\\2(?(-2)\\\\))\\\\s*;\\\\s*\\\\?>\\\\s*\n" + " (?:\\\\s*(?:<!--.*?-->))*\n" + " <master\\\\s*src=([\\\\'\\\\\\\"])(?<master_url>.+?)\\\\3\\\\/>(?<content>[\\s\\S]*)\n" + " $\n" + " /ix\n" + "PREG2;\n\n" + "$raw = file_get_contents(filter_input(INPUT_SERVER, 'SCRIPT_FILENAME'));\n" + "preg_match($re, $raw, $matches);\n\n" + "$master = file_get_contents($matches[\"master_url\"]);\n" + "$child = $matches[\"content\"];\n\n" + "$child_txt = eval2str($child);\n\n" + "$master_txt = eval2str($master);\n\n" + "$placeholder_xml = new DOMDocument();\n" + "@$placeholder_xml->loadHTML($master_txt, LIBXML_NOWARNING);\n\n" + "$child_xml = new DOMDocument();\n" + "@$child_xml->loadHTML($child_txt, LIBXML_NOWARNING);\n\n" + "$child_elems = $child_xml->getElementsByTagName(\"content\");\n\n\n" + "foreach($child_elems as $c)\n" + "{\n" + " $name = $c->getAttribute(\"name\");\n" + " $child_map[$name] = $placeholder_xml->importNode($c, true);\n" + "}\n\n" + "$placeholder_elems = $placeholder_xml->getElementsByTagName(\"placeholder\");\n" + "while($placeholder_elems->length > 0)\n" + "{\n" + " $oldnode = $placeholder_elems->item(0);\n" + " $name = $oldnode->getAttribute(\"name\");\n" + " \n" + " if(!isset($child_map[$name]))\n" + " {\n" + " $newnode = $placeholder_xml->createElement(\"content\");\n" + " $attr = $placeholder_xml->createAttribute(\"name\");\n" + " $attr->value = $name;\n" + " $newnode->appendChild($attr);\n" + " $child_map[$name] = $newnode;\n" + " }\n" + " $newnode = $child_map[$name];\n" + " \n" + " $parent = $oldnode->parentNode;\n" + " \n" + " $parent->replaceChild($newnode, $oldnode);\n" + " $placeholder_elems = $placeholder_xml->getElementsByTagName(\"placeholder\"); // \n" + "}\n\n" + "die($placeholder_xml->saveHTML()); // to end execution of the remaining code in the calling file\n" + "/*\n\n" + "*/\n" + "function eval2str($code)\n" + "{\n" + " ob_start();\n" + " eval(\"?>$code\");\n" + " return ob_get_clean();\n" + "}\n" + "?>"; final Pattern pattern = Pattern.compile(regex, Pattern.COMMENTS | Pattern.CASE_INSENSITIVE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html